.\" $NetBSD: pow.3,v 1.1 2011/09/17 10:51:53 jruoho Exp $
.\"
.\" Copyright (c) 2011 Jukka Ruohonen <jruohonen@iki.fi>
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
.\" PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
.\" POSSIBILITY OF SUCH DAMAGE.
.\"
.Dd September 13, 2011
.Dt POW 3
.Os
.Sh NAME
.Nm pow ,
.Nm powf
.Nd power functions
.Sh LIBRARY
.Lb libm
.Sh SYNOPSIS
.In math.h
.Ft double
.Fn pow "double x" "double y"
.Ft float
.Fn powf "float x" "float y"
.Sh DESCRIPTION
The
.Fn pow
family of functions return
.Fa x
raised to the power of
.Fa y .
.Pp
If
.Fa x
is negative and
.Fa y
is not an integer, the global variable
.Va errno
is set to
.Er EDOM ,
and on
.Tn VAX
a reserved operand fault is generated.
A portable application should nevertheless ensure that
.Fa y
is an integer value whenever
.Fa x
is negative.
.Sh RETURN VALUES
.\"
.\" XXX: List also the special return values?
.\"
Upon successful completion, the described functions return
.Fa x^y .
.Sh SEE ALSO
.Xr exp 3 ,
.Xr log 3
.Sh STANDARDS
The described functions conform to
.St -isoC-99 .
.Sh HISTORY
The history of the power functions dates back to
.At v6 .
